Looking for a song

Hi everybody, I am looking for a song i heard years ago but can't find it anymore. I don't remember the title nor the singer. i remember that it was a live performance, a solo, that it was a rap and that the track sounded like classical music. the rapper was first chained to a wall and then walked down the stairs. at the end, there was a gunshot and the music changed to dubstep or something like that. maybe one of you guys remembers the song? thanks :)